I’ve run into this issue as we want to be able to see subtasks on the timeline and workload features, as well as what subtask is from what project in our “My Tasks” and the only way to do that is to add them to the project—which just mucks things up and causes all sorts of issues with duplicates on reports as well.
I think it’s a fundamental problem with their architecture that prevents them from doing so.
But most complaints of my teams even using Asana is that they have the same sub tasks for multiple projects and they have no idea for which project its for